As is known to those skilled in the art of orthopedics, the practice of orthopedic surgery often includes bone modification including cutting, suctioning and the installation of a variety of prostheses. Attendant to the practice of such procedures has been the certain side effects which are potentially injurious to a patient's health. Thus, it has been known prior to the use of endoprosthesis or intramedullary devices that fat emboli are undesirably associated with fractures of long bones. The occasional mortality with endoprosthesis and cement fixation has been considered to be primarily due to pre-operative cardiac or pulmonary diseases of the patient. However, more recently, by comparison in recent years of cemented versus non-cemented components, the increased morbidity and mortality of patients with cemented endoprostheses was considered to be due probably to the use of cemented endoprostheses in patients with greater cardiac and pulmonary and other debilitating diseases and decreased mobile capabilities. The commonly observed decrease in blood pressure was considered to be primarily a result of small amount of the monomer Methylmerthacrylate being introduced into the patient's general circulation. The drop in blood pressure was believed to be effectively controlled by reducing the depth of anesthesia shortly prior to and during the insertion oft he bone cement into the canal or cavity.
With recent employment and refinement of various imaging devices and improved method of study, recognizable changes within the vascular system at various stages of endoprosthesis surgery have been shown. Multiple unidentified particles of material generally referred to as debris are now observed and timely associated with manipulation of fractures, reaming and/or rasping of medullary bone, insertion of the endoprosthesis with or without bone cement, and performing the necessary manipulations to position the prosthetic femoral head into the acetabular area.
The observation that an increased and appreciable number of debris particles reached the right ventricle of the heart at the corresponding moment of reducing the femoral head into the acetabulum is evidence that such particles have been residing in an unidentified area and are probably moved by either elevating the leg which is necessary for reducing the head into the acetabular area and/or by stretching the muscles of the area and so the debris particles are squeezed and moved into the general circulation. If the particles are considerable in number, the patient has a slow post-operative recovery period with moderate morbidity. If the patient, preoperatively, is a poor surgical risk, the morbidity may be tremendous, and to such a degree that the patient succumbs. It is therefore desirable to decrease the number of small debris particles including fat and thereby decrease the number of emboli; to remove debris at the earliest possible moment; remove most of the fat as soon as the membrane of the fat cell is broken; remove the small debris particles as soon as the cutter has created any bone-dust and other small particles; and desirable to more effectively remove or recover the remaining debris particles which are residing in or near the operative field. Furthermore, it seems proper to avoid performing surgery which involves large medullary displacement, or removal in two long bones of a patient in the same day.
Currently, in the preparation of a long bone for receiving an endoprosthesis, such as the femoral stem, some of the medullary bone and its marrow are removed to provide space for the endoprosthesis. The bone and marrow are cut by reamers and removed by suction, irrigation and brushing. By the process of cutting there are produced multiple pieces of bone which range in size from exceedingly small pieces of hydoxyapetite to easily seen and palpable sizes. The marrow in the elderly is usually yellow marrow and consists mainly of fat cells, but in the more elderly or emaciated person, the marrow may have lost most of its fat and is identified as gelatinous marrow because of its consistency and appears somewhat reddish in color. In the epiphyseal region of long bone, there may still exist red marrow with blood forming capabilities.
Generally speaking, the removal of medullary bone and marrow, the fitting and insertion of the endoprosthesis, and the cementing of the endoprosthesis in the canal, produces debris which may consist of many different things such as clumps of blood cells, clumps of endothelial cells or bits of pieces of fibrin from vessels and cell walls, fat, pieces of bone or hydroxyapatite, and bits of Methylmerthacrylate mixed with any of the other debris, or bits of poorly polymerized or incomplete polymerization of Methylmerthacrylate.
Currently, the portion of medullary bone which is to be removed is broken up and cut up by reamers which have a cutting edge at the advancing end of the shaft and spiral grooves up the periphery of the shaft of the reamer. A reamer is therefore quite similar to a drill bit. For easy operation and speed, the reamer is often power driven. The reamers are usually used in sequence of increasing size of their cross-section diameter, thereby attempting to avoid overloading the spiral grooves with debris. However, such a system and method is accompanied by displacing some small sized particles of solid or semi-solid debris distally of further down the medullary canal, and some are moved outward to the surrounding intertrabecular spaces of the medullary bone. Broken fat cells permit the fat to be easily displaced, distally and outwardly. Some of the debris which remains in the canal, as each reamer is changed or removed, is withdrawn by suction. When the medullary canal has been reamed by the largest selected sized reamer, the canal is irrigated and suctioned and brushed repeatedly in an effort to recover the debris that rests in the intertrabecular spaces. However, some of the debris has been moved too far distally and outwardly to be recovered by brushing, irrigating and ordinary suction.